With most of the world’s population now living in cities, policymakers are exploring new ways to make urban expansion sustainable.
Building an urban paradise
Building an urban paradise
Located along the southern bank of the Yellow River, Kaifeng, the capital of the 11th century Song dynasty, was probably the world’s first ever metropolis. During its heyday as East Asia’s main trading hub, the city was home to almost one million people, mostly subsistence farmers who had abandoned the countryside in search of a better life.
More than one thousand years later, China is still very much in the grip of urbanisation. But today’s city expansion is of an altogether different scale. As many as 1.8 million people are now moving from the country into Chinese cities every single month – the equivalent of nearly two 11th century Kaifengs, or the entire population of modern-day Vienna.
Although the most extreme example, China is not alone in experiencing an urban explosion. The United Nations estimates that more than 60 per cent of the world’s population will be living in cities by 2050, compared with just 3 per cent in 1800.
In some ways, urbanisation is to be welcomed. It can lift people out of poverty and create a better-educated and more productive workforce.
However, it also produces some harmful side effects.
Although they take up just 2 per cent of the world’s land mass, cities consume almost 80 per cent of its energy and are responsible for about 60 per cent of its greenhouse gas emissions. So the more urbanised the planet becomes, the less hospitable it promises to be.
This is why a growing number of cities are striving to become more sustainable and climate-resilient.
One way they hope to do so is through global initiatives such as C-40.
This is the name given to a group of 75 of the world’s major metropolises – including London, Lagos, Johannesburg and Jakarta – that have joined forces to promote urban sustainability and invest in technology to reduce CO2 emissions.
Representing more than 550 million people and one quarter of the global economy, C-40 is at the frontline in the battle against urban induced climate change.
“The steps that cities take to shrink their carbon footprints also reduce their energy costs, improve public health, and help them attract new residents and businesses”
“The steps that cities take to shrink their carbon footprints also reduce their energy costs, improve public health, and help them attract new residents and businesses,” Michael Bloomberg, the UN Secretary General’s Special Envoy for Cities and Climate Change and President of the C40 Board, wrote in a recent paper.
The financial gains associated with sustainable urban development could be considerable. According to the consultant McKinsey, the investment required to expand urban “green districts” – densely populated areas which make use of the best available sustainable technology in water treatment, energy efficiency, transport and waste recycling – can be recovered within just five years.
Waste to power
Reducing municipal waste is among the major headaches for urban planners. Refuse is a huge environmental problem across cities worldwide. World Bank figures show that every person living in a city produces an average of 1.3 kilogrammes of waste per day – double the amount a decade ago. By 2025, the figure is expected to rise to 1.42 kilogrammes.
Currently, most of that waste is either sent to landfill or incinerated . But a growing number of cities are turning to technology to put this refuse to more productive use.
The Brazilian metropolis of São Paulo, the world’s tenth most populous urban centre with some 20 million inhabitants, is among those that have invested heavily in new waste-to-power infrastructure to reduce its carbon footprint.
The Bandeirantes Landfill Gas to Energy Project to the north of the city is perhaps its most successful initiative. Working in partnership with private company Biogas Ambiental, authorities in São Paulo have built an energy plant that converts methane emissions from landfill into energy. The facility has reduced the metropolis’s greenhouse gas emissions by 11 per cent.
Singapore’s progress has been more rapid. The city state already burns 38 per cent of its solid waste to generate electricity and recycles the remaining 60 per cent, sending only 2 per cent to landfill. It is planning to build its fifth waste-to-energy plant by 2019.
But turning waste into something useful can also be achieved through more modest projects.
San Francisco, which plans to move to zero waste by 2020, offers a “pay as you throw” trash-metering incentive to businesses that cut waste. The measures have met with considerable success – the city currently recycles or composts 78 per cent of its waste, more than any other metropolitan district in the US.
City authorities are also looking to cut energy use, particularly electricity, where there is plenty of scope for improving efficiency.
Take street lighting – it accounts for a hefty chunk of municipal power bills but is often used to light up empty streets.
Energy-efficient bulbs are one solution.
Kolkata and Mumbai are among 100 cities in India which will replace 770 million conventional bulbs in streets and households with LED lighting by 2019. This alone will slash annual electricity consumption by nearly 60 per cent.
Barcelona, meanwhile, is rolling out thousands of solar- and windpowered street lights and connected LED lamps which can be switched on and off from a central control room. Already, self-powering lamp posts light up a palm-lined promenade on Barcelona’s famous waterfront in the evening.
The Spanish city expects to achieve energy savings of around 40 per cent, but there are other positive effects. Studies have shown over the years that improved street lighting can significantly help reduce crime.
“The number of light points increased since we added specific sidewalk lights. That meant that savings are not so big but public perceptions (about personal safety) have improved considerably,” says Clara de Yzaguirre Pabolleta, a spokeswoman for Barcelona City Council.
Copenhagen has taken a different approach to energy efficiency. It has built a district heating system which recycles waste heat from electricity production to warm 98 per cent of the city with connected steam pipes.
For Tokyo and Yokohama, meanwhile, the challenge has been how to keep cool, not warm. City authorities there have focused on tackling the urban-heat island effect, covering roofs and walls with lightweight greenery to lower the surface temperature of buildings.
The economics can work
The measures that C-40 members are taking may seem small when seen in isolation. But together, they could have an enduring impact on the environment.
Just as importantly, they can also contribute to economic growth. A recent report by the Global Commission of the Economy and Climate found that investing in lower-emission public transport, using more renewable energy and increasing efficiency in commercial buildings and waste management in cities could cut energy costs by about USD17 trillion worldwide by 2050. Sustainable urban expansion is not only good for the planet, it can also be good for the economy.
“Instead of being afraid of climate change because the cost is scary – which is a prevalent view – our analysis shows that tackling climate change at a city scale can be economically beneficial”
“Instead of being afraid of climate change because the cost is scary – which is a prevalent view – our analysis shows that tackling climate change at a city scale can be economically beneficial,” Andy Gouldson, Professor of Environmental Policy at Leeds University and one of the authors of the report, explains. “And the net effect on climate change is so significant.”
Knowledge share key
For sustainable initiatives to gather momentum globally, cities must be willing to share their technical expertise and experiences. The Compact of Mayors, which brings together the leaders of the world’s largest cities, aims to encourage just that. Working with the UN, its members are tasked with tracking and reporting on the progress of environmental initiatives.
Such co-operation is essential in a century that will see the emergence of many more “megacities” – sprawling metropolises with more than 10 million inhabitants.
“Megacities will need more mega-facilities. Expect more new investment in infrastructure from 2020 to 2050 than in all human history – schools, hospitals, power stations, national grids, water supplies, sewage treatment plants, roads, railways and airports,” says Patrick Dixon in his book The Future of Almost Everything.
“Every architect, builder and city planner will be expected to think about sustainability in future.”